1. Field of the Invention
The present invention relates to a substrate processing apparatus to process a substrate. Examples of substrates to be processed include semiconductor wafers, substrates for liquid crystal displays, substrates for plasma displays, substrates for FEDs (field emission displays), substrates for optical disks, substrates for magnetic disks, substrates for magneto-optical disks, substrates for photomasks, ceramic substrates, substrates for solar cells, etc.
2. Description of Related Art
In a manufacturing process for a semiconductor device or a liquid crystal display device, etc., a substrate processing apparatus is used to process substrates, such as semiconductor wafers, glass substrates for liquid crystal display devices, etc.
Japanese Patent Application Publication No. 2010-56218 discloses a substrate processing apparatus of a single substrate processing type to process substrates one by one. The substrate processing apparatus, in order to prevent the substrate from being oxidized by oxygen contained in a processing liquid, supplies a liquid containing inert gas dissolved water from which oxygen has been degassed and to which nitrogen gas has been added as the processing liquid to the substrate. Further, the substrate processing apparatus, in order to suppress a rise in the concentration of oxygen in an atmosphere that contacts an upper surface of the substrate, covers the substrate disposed over a spin base with a shielding member having a substrate opposing surface and a peripheral wall portion.
In a manufacturing process for a semiconductor device or a liquid crystal display device, etc., it is demanded in some cases to process a substrate in a state where the concentration of oxygen in the atmosphere is considerably low.
As described in the publication mentioned above, even when the concentration of oxygen in the processing liquid is low, because oxygen in the atmosphere dissolves in the processing liquid if the concentration of oxygen in the atmosphere is high, the processing liquid the oxygen concentration of which has been raised may be supplied to the substrate. Also, watermarks caused by oxygen in an atmosphere may occur on the substrate if the substrate is dried in a state where the concentration of oxygen in the atmosphere is high. It is therefore necessary to reduce the concentration of oxygen in an atmosphere in both of the liquid processing process and drying process.